Revamp the API once again

Another look at the current API showed some inconsistencies, rectified
in this commit:

libevdev_kernel_*: modify the underlying kernel device
libevdev_event_type_*: something with an event type
libevdev_event_code_*: something with an event code
libevdev_event_*: struct input_event-related functions (i.e. not device-related)
libevdev_property_*: something with a property
libevdev_*: anything applying to a device

Hopefully that's the last API change. Current symbols deprecated and aliased.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Acked-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Add missing group assignment to a bunch of functions and enumerations

Without these, they won't show up in the documentation.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
doc: don't show enum values in doxygen

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Fix comment typo

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>